PBX3 and acute myeloid leukemia: We then overexpressed Pbx3 in P2x1-null AML cells and demonstrated that its ectopic expression enhanced AML progression in recipient mice as indicated by increased leukemic cell frequencies in the peripheral blood (Fig. 4A, B), reduced overall survival (Fig. 4C, D) and enhanced infiltration in spleens and livers (Fig. S4A).